All vanadium redox flow battery, which is called vanadium battery for short, is a kind of redox flow battery. With advantages of long service life, high efficiency energy conversion, high security, environment friendliness and so on, all vanadium redox flow battery, which can be applied to a large-scale energy-storage system supporting wind power generation and photovoltaic power generation, is one of the major choices for peak load shifting and load balancing of grids.
A vanadium battery is mainly composed of three parts: an electrode material, a battery diaphragm and an electrolyte, wherein the electrolyte, which is the core of the vanadium battery, is a vanadium polyvalent system to realize energy storage and release of the vanadium battery. The vanadium battery applies solutions of vanadium ions having different valence states as active substances of the anode and cathode respectively. The electrolyte circulates in a storage tank and a battery tank through an external driving pump, and redox reactions of the electrolyte at the anode and cathode occur on electrodes at two sides of an ion exchange membrane in the battery pack, thus completing a charging and discharging process.
The equations are as follows:Cathode reaction: V2+−e=V3+ E0=−0.26VAnode reaction: VO2++2H++e=VO2++H2O
In the whole all vanadium redox flow battery energy-storage system, the performance of the battery pack determines the charging and discharging performance, especially the charging and discharging power, of the whole system. The battery pack is formed by stacking and tightly pressing a plurality of individual batteries, and connecting the batteries in series, wherein FIG. 1 shows general components of an individual battery. 1′ is a flow frame, 2′ is a collector plate, 3′ is an electrode, and 4′ is a diaphragm. An individual battery 5′ is composed of pole plate pieces and a battery pack 6′ is formed by stacking N individual batteries 5′. In use, the values and distribution of corresponding parameters including the internal temperature, pressure, and state of charge etc. in the flow battery pack have great influence upon the performance of the battery system. In the prior art, these performance parameters are generally acquired through simulation of hydromechanics etc. or are acquired indirectly. For example, the performance parameters are monitored outside the battery. It is of great importance to acquire the real values of correlative parameters of the interior of the battery pack and distribution thereof to verify and guide operation control, system design and optimization etc. of the battery. However, there is no technology or device capable of observing correlative parameters of the interior of a battery pack in situ at present, and monitoring of battery performance parameters in different flow field designs can be hardly realized by the prior art.